Transformer apparatus



J. KUBLER TRANSFORMER APPARATUS A r-i121, 931.

Filed Aug. 24, 1927 2 Sheets-Sheet l If I I April 2-1, 1931.

J. KUBLER TRANSFORMER APPARATUS Filed Aug. 24, 1927 2 Sheets-Sheet 2 j commmmen of eenager. ff mbodyingfthe invenfion.

' lat I e miiiimum eostit is impoi tantthatthe .transshell be p'e rfectly balanced end-symmetrical, 3Q,

licat on flled"Qugust'fl,1192?,fierit1jgo.

P invention I 'eIa-tes to transformer, mp pai'atus "aid has parti eillm' relarttoh to traps time? apparatus msed -i-n QOmblflfltlUfl with r H triple-"phase redtifiersior QOII VGI f/IIL g quartet "15 pha seteurrentsintocdirecteuryent. y

Among the obj ects of the jmventton 1s ap improved trans fiormer {of the foregomg charaeter and'dts combination with a frectlfier echaraeteiized byan arrengementofthe atrztns former windim gwhieh secures balanced eer- "rent *a lifl the Voltage conditions,- 1' pennlts establishment of e Trielitral point "of 'predeter mmed potential iii the uarter-pha e: system exit]. secureseflieiene off opemtion with econy f eli [Sp ,z w 11-]; The forego'ilgyf 1 1d ether ob eats of the m- Yventi-om Willbe "best understood t am the 1501- lowingdesc-riptions of exe'mplificatlon theren m ceb i h d: t h c em y elm-Wings whammy 1 l Fig.1 is hficirou" Qmjis iiflvedtol diagram sfllustmtilig the phase relationship the winding c 'onnee tionsfof the j pr'imery winding of the trans; lforln'efof'Ei'g. 1; I

o 'ise circuit diagram i llttst rlating ta ii ees' fier :system Zwherein, two g rm s rm inifits of thetypefsholv vn a r e combined A Fig. '4 s acircuit diegr'amof a system slml ar 'to' F 3 utilizing a; different form oftransfornier. 1'

Forith"eonirersion of quarter phese cflr- Q :rmt-ihtogdirect fclir nent. in largepowerf ihstallations, ift is desirable ,:to' use fmereory vapor rectifiers ofthetpiple phesetypeg that either three pha es or a multiple there .1 ofk To" secure satisfactory opetetionete a former pp sifer upp y n s whkr fi One of thej ffeatures"of ffthe'lihvehtioii the pi ov ision o ftwh improved "wihding system ing a neutral twpplin g point for quarter-phase two j'independen t phases or with three-wire .stitute a short eii'cLiit-on the system. A tournot eoin'cidefwith theneutral point ofthe lo'adi Uniersuch eonditionsgthere W iIIFtake 5 XULBLEB, 1 13531211, flswizrzmexb, hesitat on T0 Akrp mneitsemscnhmf 01 n, QOF JBADEN, SWITZERLAND, A JOINT-STOCK column! or t mssemmgsrmws particularly suitable for use in transionme-l s of-the foregoing type for eonverting quarterphase current into tl igp'le phase current and adapted coserve also use means for establish systems. Such neutral tapping point is ordinerily not 1p=resent in :two-p'ha se alternat i gmurrent systems because they usual-1y "0p epaite either: with founw ire systems; having systsrhsjnswh-ieh an entl oi one phase is joined toan enc'toftheother phase; Both typesloi eonneetions are unsuitable wheri thek two-phase network has to supply apparatus or Windingshzwi-ng finterlinkage points that have mo correspondmg 'polnts "1n the network Forj instailee, 'When reeti fiers'are to be op erateclg as eicp lained above, it is heeessary to V have alstap or junction point which cor-respends r t-o the neutral point of the system {antler eohc'litfons of symmetry. If the-feet? fier has three anode phases it will be neees sii-r y to supply the same from etwo-phasefifi three-phase t ra sformerg the primary wind *mg of =Wh1ch may, 111 a glven easegbe SO-Jlll 17:5 tereonneeted that the junction poi nt of the phases is the nel l'tmTpoint of the system. t fStlch -loatieennot he {eonliected to' a twophase three-Wife system since it would con- Wi t-e "quarter-phase system with non-intelf Al-hiked phases will also operateunsatisiac tori lyjolf shdh load if the symmetry should iri 'any w 'vayhee omedisturbed; For example, if the line conductors have difierent partial "cepacities to ground or different insu'letioh resistance, the natural position of the neutral *1 f pointof the network, Whose potential differ enee with respect to 'the ground is zero, will high i allies en d represent a Very undesirable load, both on-the netivotkand on the load t apparatus thereofl resent inventioliiesi des to v term for connection to apparatus that interlinks'the network in the neutral point ofthe;

system by providing on said system a neutral point and grounding the same. This absolutelylprevents" any displacement of 'the neutral'point ofthe network-and definitely fixes the relative potentials-of the system.

i As suchneutral point may beused, either'the H neutral point ofthe winding of a generator.

or? load apparatus that operates on thesystem, or the neutral point maybe obtainedby means 7 ofa special winding connected. to the system and having a neutral tapping connection thereon. The equalizing connection will bemost efi'ective withthe neutral pointdirectly connected tothe groundj' However, thishas the disadvantage that in caseof ashort'circuit automatic disconnection of the network is required. T01 avoid thesedifliculties the neutral pointmay be grounded either through a resistance or through reactors,.preferably h through an inductance arranged so as to compensate'the current-tending to flow 'tofa" ground fault, as explainedin the periodical of 7 'Brown Bove'ri & Cie-;6,ntitled"BBC Mitteilungen of May'l921,p.7l.etc. 1

. Inorder that the; current flowin'ginlt'he groundingi'connection shall, not be impeded by the action of the equalizing windings,1a

neutral-point; tapping transformer may" be usedfor this purpose. Such transformer is similar in nature to a static balancer having windings distributed on amagnetic corehavingtwojor.more-jphases or core legs. 'Ifa V two-phase design is adopted, thej neutral tapping transformer is arranged with 1 :two core legs and two phase windings '1 mounted thereon. II"; av three-phase? construction is 1 jadopted,thetransformer comprises a three- 4O phase Winding on three core legs, the number ofturns being so chosen and the connections being so made as to, give 'tapplng points for 1 operating ona two-phase system and also a pointof thetwo p'hasesystem.

junction point; corresponding to the neutral 7 HA; transformer and w nding arrangement whiohembodiesthe [features of the invention pointed outabove is shown by way of. example in Eigsgfl and 2 illustrating an organization -wher-ein attire-phase supplyline I, II-is ar ranged to supply'balanced alternating "cur-I rentfto arsix-phase mercury-vapor rectifier 2, having" a cathode 3 and six anodes 4.] In order ,to" transform thequarter-phase our rents-of the supplyfline Lll'intoisixphase ycurrents'for therecti'fier 2,I utilize a special transformer 5 comprising aQthree phaseffcore 6,having-three core legs Mounted-on said I transformer core 6; is'a' siX-phasestar- On nectedsecondaryl winding. 7 having its end f terminals connected'to the anodes 4 01, the rec itifie rifand a primary winding ,8 arrangedso asto maintain balanced current and vyoltage' :Tcondition, both" in the three pha se connections to therectifienaswellasin the quarterephase connectionsto the supplyline I, I I. The primary winding. 8 is so arranged as to also pro- 1 vide a neutral tapping point for the quarter phase system for connecting agrounding device such as an inductance coil 9 thereto, thereby fixing the voltage relations of the system V i V r V i I Asseen from Fig. 2 in Which the various elementsof the primary winding 8 are repre i sentedby thelvectors of the voltages'induced therein, respectively, said winding comprises twosets of winding sections B G and A ,'B C the Voltage vectors of which constitute two symmetrically disposedequilat eral triangles, a, b, c'fand c,d,'e, with a comwinding sections A A belonging toi vone' phase and the winding sections'B B belonging to the otherjphase, and-arranged re-;

.spectively on two difierent phases or legs of the core, are ofequal length and encloseajphase angle of and 1209;, respectively, the

voltage yectors representing Qsaidwindin'gs, crossing eachother in the'form o fan X, the windings being joined. at the' point corre; it spending totheintersectionof said Ive-ctors, 7 Theco-phasal winding sectionsC rC which join the end points ofthe twolpairs of, said Xconnected.winding sections: A A and B B are disposed on-the thirdzphase or leg of the transformerjcore and. have-:co phasal ex- 7 o s GrGfl, E,- 72 S0 .thatth ee spondingvoltagevectors define a square,'t he four corners of which constitute: terminals nected to said terminals. 3 i

i W W Il iIigar-rangement trialstraine i Will. readily serve as a means forxdefining the potential of'the system with respect to the ground by providing a grounding connection plying threephaser'ctifiers', or general,

rectifiers havinga multiple or threeephases. With such arrangement, balancedvoltage, H current and flux conditions willbei main tained, both withrespect to the three-phase "system, as wellas-with'jrespect tothe two phase system, and balanced three-phaseflux" fluctuations will obtain in. thelxtransformer core 6.

f .111 manyjcases, l tween the X connectedphase windings A o' 'l Os, i i ey the dt m b of the X-lconnected windingsfimay:jbe,,the cause of sli'ghtunbalan'ce in the voltagefand current conditionsofthe rectifier system and T 1'1, 12,13,14jjiorconnectionto atWo-phase V c I i a system, the two-line phases; I, i-II] being con so monju'nction point at cconstitutingtheineutral point of the system, In other words, the

.95 ii i and being symmetrically disposed; with ;respect to saidpoint-of intersection, the points lateral triangles symmetrically disposed, on as I The principles of the invention in'connection with the above described exems 'plifications of t1ieinvention will suggest tof those skilledlini the art many other forms and modifications thereof, and it is-acoomiingly desiredthat the appendedclalms be given a scope ofthe invention". i I claimi' prising a three-phase core, two X connected 5 phase windings disposed-Ton two diiferent I a 15 phases of} said 5 core, respectively, "and; :two

" additionaliphasef windings disposed on the third core phase, said additional windings connecting respectively the end terminals of said two X-connected phase windings and having ektensions :projecti-ng beyond ;the pointsof'i-unctionwith said windings, the number 7 of turnsand relationship of said windings being such that the ;voltage vectors of said two -X-connected'windings'define two equilateral trianglessymmetrically disposed on opposite points. of 1 the intersec; tion "of said "two windi11gs, the end points of the: Voltage vectors 0fSfldffldditiOIlZLl-iZWO windings constituting two sides-of "a square enclosing zsaid intersecting-, voltage vectors of "said jadditional Iwindings corresponding quarter phas'e i terminals of said transformer; the point of intersection of said two X-cojnseated windings constituting a neutral-"tap w ping connectionJ j i h i fer-phase currents into n phase currents, or vice versa, n being determined. by the-equation rt 32 comprising; an qt-phase core, a

balanced a -phase winding arrangedfon said for connection to a qu'arter-phase'line;said quarter-phase w nd ng comprlslng two phase-windings enclosing an angleof 0 mm having afliunctioii at their midpoints so that the voltage vectors thereof define two equiopposite sides of said junction itwo Qaddie tional' phase windings of'a phase corresponding to the open sides ofjthe tri angles' formed 'plementing [said triangles, said] additional phase windings' having co phasal extensions beyonjd'fthe points of junction ,With fsaid 0 X connected windings, the voltage vectorsdefiningopposite sides ofaisqu'aresymrnet corresponding .to said additional windings rically enclosing said X -connected windings, the-points ofsaid additional windings correline, first V transformer J for transforming broad construction commensurate with the o 'quarter phase current from saidr line into o Q n-phase current, twosimilar-loadssupplied "1; 1A neutral tapping transformer" oom? primary 'windings; oi" said'ft'wo' 1transformers being "connected: to di fierent phases of said f quarter pha'se line, i and 13111 interphase tran s; I o 'formerinterconnectingsaid loads with said to the corners of said squareconstituting the.

2; A transformer for'transrorming "quar to said linen phasesecondaryjwindings, n

core for connection to an- 'n-phase line; and a quarte'r phasewindmg arrangedfon said core by said *first mentioned windings and comwindings; said j unction point otisaidaXscom neoted, windings being of neutral potential] with respect .to said quarter-phase terminals.

3. lhe combination of *a "quarters-phase 7b quarter-phase current from said lineafto' n-phase current, n being determined the equation 41 32, a"second-"transformer"similar to the first transformer for transforming respectively .ffrom I said transformers .with

n-phase currents, said: two transformers'hav ing similar "winding Iarrangement with two sets of corresponding; quarter phase' 1ter-' 'minalsjfor connectiontosaid quarter-phase line, the" connections of said "quarter-phase terniinals tothe phases of said line-being L cyclicall 'rotatedin said two transformers, g

to interlink thecurrentfiow in the' secondary v pliedgl'espectively by said} secondary-"windings, corresponding pairs of terminals of the secondary Twindings to interlink the current. flow 1n the secondarywindingsof saidtransf formers. i

being letermi'ned floy the equation) n =3.2 f', similar nfphase loads connected respectively 1 to said secondary windingss corresponding 1 7 pairs oftermin'alsof said two primary windings being cyclically connectedfto different phases of said quarter-phase line, an in ter-phase, transformer interconnecting said loadswith said secondarywindings to inter-l link the current flow in the econdary windings of saidtwo transformers.

6. In transform r apparatusy": windings connectedto. each other intermediate -j=heir" respective fends to providea fneutral-jpoint for said apparatus and being of} diiierent connected at points intermediate its ends 5 to the respective adjacentr terminals of said first-named windings oni oneiside "of .fsaidj point, said winding being ofiphase different "from'therespectiyephases oftsaid crammed v -windings,and another'winding connected-at '1 a points intermediateits ends to the respective L .i spondi'ng toj the corners of'said square conr stituting. the quarterphase terminals ofj 'said adjacenttelfminals of said first-named wind-I a a 12a phase withrespect 'to each other, a windin'g In testimony whrbof I fiafehreuhto 511b; 1

scribed mynamefthis 9thyda "of August, A:

JOHANNESYK 1 

